Avian encephalomyelitis

Avian encephalomyelitis is a viral disease of poultry, mainly chickens and turkeys, caused by a picornavirus of the genus Tremovirus. The disease affects the central nervous system of young birds and can cause severe economic losses to the poultry industry. Typical symptoms include ataxia (movement disorders), head and neck tremors, leg and wing paralysis, general weakness and high mortality. Drowsiness, loss of appetite and diarrhoea are also common in infected birds. In adult laying hens, infection may cause a temporary reduction in egg production. The disease is spread horizontally by direct contact between birds or vertically by transmission from the infected hen to the eggs.